NEW YORK — Ruby Dee, an acclaimed actor and civil rights activist whose versatile career spanned stage, radio television and film, has died at age 91, according to her daughter. Nora Davis Day said Thursday that her mother died at home in New Rochelle on Wednesday night of “natural causes.” Dee, who frequently acted alongside her husband of 56 years, Ossie Davis, was with loved ones. Her long career brought her an Oscar nomination at age 83 for best supporting actress for her role in the 2007 film “American Gangster.” She also won an Emmy and was nominated for several others. Since meeting on Broadway in 1946, she and her late husband were frequent collaborators. Their partnership rivaled the achievements of other celebrated acting couples. But they were more than performers; they were also activists who fought for civil rights, particularly for blacks. Davis died in February 2005. Among those who mourned at his funeral included former President Bill Clinton, Harry Belafonte and Spike Lee. Davis and Dee met in 1945. They shared billing in 11 stage productions and five movies during long parallel careers. Dee’s fifth film, “No Way Out” with Sidney Poitier in 1950, was her husband’s first. Along with film, stage and television, their richly honored careers extended to a radio show, “The Ossie Davis and Ruby Dee Story Hour,” that featured a mix of black themes. Among her best-known films was “A Raisin in the Sun,” in 1961, the classic play that explored racial discrimination and black frustration. On television, she was a leading cast member on the soap operas such in the 1950s and 1960s, a rare sight for a black actress then. She won an Emmy as supporting actress in a miniseries or special for 1990s “Decoration Day.” She won a National Medal of the Arts in 1995 and a Lifetime Achievement Award from the Screen Actors Guild in 2000.